CH pressure drop + plaster damage

[whatamess]

I am thoroughly fed up... any thoughts appreciated.

This evening I noticed for the first time that a skirting board on an internal wall on the ground floor of a house had seperated from the wall. It was fine a week ago. A quick look around the other side of the internal wall (i.e. another room) shows the same problem... my initial reaction was some foundation problem.

However in my blind panic running around the house trying to work out what the cause was, I have noticed that the central heating pressure has fallen from 2 bars (last checked it 3 weeks ago) to 0.0 bars. It normally loses perhaps 0.1-0.2 bars per year, if anything.

Central heating system (boiler+tank) ~10 years old.

My questions:

(1) Is it sensible to conclude that an underfloor central heating pipe has sprung a leak?
(2) I still have hot water from the tank and hot radiators... how can it still be working without any pressure?
(3) What happens if I keep using it without any pressure?
(4) Are my fears that someone is going to have to rip up most of the floor to try to find the leak warranted? How do plumbers do exploratory surgery on a CH leak without destroying the house!?

Would really really appreciate any comments.

 

[ChrisR]

1) it's a fair bet
2) It won't for long. You risk a dry pump and boiler, which will wreck both. There's no pressure switch so it won't know
3) Armageddon
4) Yes, and Plumber/Surgeons are thin on the ground. Think Kango drill chiselling big holes in your floors. The Good news is you won't get anyone to do it before Christmas...
Sorry.

 

[Softus]

(1) Is it sensible to conclude that an underfloor central heating pipe has sprung a leak?

You might be jumping to a conclusion, but certainly you've started looking in the right place.

(2) I still have hot water from the tank and hot radiators... how can it still be working without any pressure?

Rads depend on the boiler, but is the DHW tank open-vented and gravity fed?

(3) What happens if I keep using it without any pressure?

Depends on the boiler. Pumps don't like it though.

(4) Are my fears that someone is going to have to rip up most of the floor to try to find the leak warranted?

Yes.

How do plumbers do exploratory surgery on a CH leak without destroying the house!?

It's like a spot-the-ball competition - skill and judgement. In obscure cases an infra-red camera is useful.

 

[whatamess]

Thank you both very much.

Softus - not sure if the tank is gravity fed. However its on the first floor, together with the pump, and the boiler is on the ground floor. Pressure can be increased by opening a screw with a screwdriver - there is a small silver flexible pipe about 12" long which the water flows into the system through when this is done. I haven't increased the pressure because I am assuming that will just cause more water damage as it leaks out. I suppose that is the best test to confirm the leak.

The pump and boiler both seem ok at the moment. I had a chat with a plumber who may be the chap who does the work and his view (he knows the house quite well) was that it will increase the load on the pump, but for a week or so he was not overly concerned.

We have turned the thermostat down to try to reduce the load a bit.